Spinal implants and instruments

ABSTRACT

An intervertebral spacer inserter includes a sleeve having a longitudinal axis, a hollow sleeve bore extending through the sleeve along the longitudinal axis, a sleeve tip end and an opening of a passage disposed in the sleeve tip end. The passage extends into the sleeve to the sleeve shaft along a passage axis that intersects the longitudinal axis at an angle less than about 90°. A sliding tip with an elongated slot is in contact with the sleeve tip end and is moveable with respect to the sleeve tip end between a first position with the opening accessible through the elongated slot and disposed adjacent a first end of the elongated slot and a second position with the opening accessible through the elongated slot and disposed adjacent a second end of the elongated slot opposite the first end.

FIELD OF THE INVENTION

The present invention relates to implants and instruments for use inspinal surgery.

BACKGROUND OF THE INVENTION

Repair and stabilization of the thoracolumbar region of the spine forcoronal plane and sagittal plane reduction and intervertebral spacerinsertion utilizes various tools and implants. These tools provideaccess to the thoracolumbar region, insertion of spacers, insertion ofpedicle screws and other anchors and attachment of rods to these screwsand anchors. Improved tools for anchor insertion, rod reduction,reduction screw tab removal and spacer insertion are desired.

For example, various techniques are currently being used to fuse lumbarspine vertebrae to treat specific types of spine disorders and toalleviate pain. These include the minimally invasive procedure laterallumbar interbody fusion (LLIF) that accesses the intervertebral discspace and fuses the lumbar spine using a side (lateral) surgicalapproach rather than a front (anterior) or back (posterior) approach. Asa minimally invasive approach, LLIF reaches the spine through severalsmall incisions, reducing tissue trauma, scarring, post-operativediscomfort and pain medication use.

The LLIF approach facilitates a 90° vertical reach parallel to the discand the posterior wall of the vertebrae. Specifically in patients withcoronal deformity, discs are often approached from the concave side,which permits easier access and reduces the number of incisions.However, access to L4-L5 makes an exception due to the position of theiliac crest. In patients with a coronally oblique L4-L5 disc and a highcrest, a convex side approach is used. If the mid lumbar concaveapproach and the side of the L4-L5 approach do not correspond, acontralateral L4-L5 approach is used. After posterior fixation, tablebreak cannot be used to open the space between the ribs and the iliaccrest. Therefore, L4-L5 cannot be reached without angled measurements.

In addition to the limited number of disc levels that can be accessed,patient specific anatomy can provide for only a left or right approach.Before surgery, the width of the working window to each space is checkedby looking at the position of the vessels and lobar plexus in axialMRI/CT slices. Depending on the axial anatomy, one side could beconsidered safer for access than the over side.

Angled inserters that are connected to intervertebral spaces having acentered attachment point allow for the instrument to be used for both aleft approach and a right approach. However, if the attachment point ofthe intervertebral spacer is off center, then two separate inserterinstruments are required based on the direction of approach. Theseseparate inserters have a fixed alignment and spacer attachment based onthe direction of approach. Therefore, a single angled inserterinstrument is desired that can be used for both left and rightapproaches during an LLIF procedure.

SUMMARY OF THE INVENTION

Exemplary embodiments in accordance with the present invention aredirected to methods and systems for using an angled intervertebralspacer inserter during a LLIF procedure in the thoracolumbar region ofthe spine and in particular in the L4-L5 disc level. The instrumentassists in access to the desired disc level during an LLIF procedure andis used to reach the upper levels of the lumbar spine where, dependingon patient specific anatomy, ribs may interfere with a 90° verticalapproach during the LLIF procedure. Suitable embodiments connect to anintervertebral spacer having an off centered point of connection forpurposes of either a left of right approach.

In one embodiment, an intervertebral spacer inserter is provided havinga sleeve with a longitudinal axis, a hollow sleeve bore extendingthrough the sleeve along the longitudinal axis and a sleeve tip end. Anopening of a passage is disposed in the sleeve tip end, and the passageextends into the sleeve to the sleeve shaft along a passage axis thatintersects the longitudinal axis at an angle less than about 90°. In oneembodiment, the angle is about 15°. Alternatively, the angle isadjustable up to about 90°. A slap handle is attached to the sleeve at ahandle end opposite the sleeve tip end. In one embodiment, the sleevetip end includes a flat surface. This flat surface is disposed in aplane perpendicular to the passage axis, and the opening disposed in theflat surface.

The intervertebral spacer inserter includes a sliding tip having anelongated slot. The sliding tip is in contact with the sleeve tip endand is moveable with respect to the sleeve tip end between a firstposition with the opening accessible through the elongated slot anddisposed adjacent a first end of the elongated slot and a secondposition with the opening accessible through the elongated slot anddisposed adjacent a second end of the elongated slot opposite the firstend. In one embodiment, the sliding tip has a first face in contact withthe sleeve tip end, e.g., the flat surface, and a second face oppositethe first face. The elongated slot passes completely through the slidingtip from the first face to the second face. In one embodiment, the firstface is shaped as a channel having a bottom surface, and the sleeve tipend extends into the channel such that the flat surface is in contactwith the bottom surface of the channel. Suitable shapes for the channelinclude a dove tail shaped cross section.

The elongated slot has a midpoint between the first end and the secondend. The opening is accessible through the elongated slot between themidpoint and the first end when the sliding tip is in the firstposition, and the opening is accessible through the elongated slotbetween the midpoint and the second end when the sliding tip is in thesecond position. In one embodiment, the sliding tip has a first edge anda second edge disposed opposite the first edge and defining a lengthbetween the first and second edges. The elongated slot is alignedparallel to the length. In addition, the sliding tip has a pair of tangsextending from the sliding tip away from the sleeve tip end. One tang isdisposed at each of the first edge and the second edge of the slidingtip.

The intervertebral spacer inserter also includes a first alignmentmechanism disposed between the flat surface and the first face to holdthe sliding tip in the first position and a second alignment mechanismseparate from the first alignment mechanism and disposed between theflat surface and the first face. The alignment mechanism holds thesliding tip in the second position. In one embodiment, the firstalignment mechanism includes a first recess disposed in the first face,a first cavity disposed in the flat surface and a first spring loadedball plunger disposed in the first cavity and biased outward from thefirst cavity toward the first face. The first spring loaded ball plungerengages the first recess when the sliding tip is in the first position.Similarly, the second alignment mechanism includes a second recessdisposed in the first face, a second cavity disposed in the flat surfaceand a second spring loaded ball plunger disposed in the second cavityand biased outward from the second cavity toward the first face. Thesecond spring loaded ball plunger engages the second recess when thesliding tip is in the second position.

The intervertebral spacer inserter includes a drive shaft rotatablydisposed in the hollow sleeve bore. This drive shaft has a distal enddisposed adjacent the sleeve tip end. A connection tip is rotatablydisposed in the passage and is in contact with the distal end of thedrive shaft. This connection tip has a threaded end that extends throughthe opening and the elongated slot. In one embodiment, the distal end ofthe drive shaft is shaped as a ball, and the connection tip further isprovided with a socket end opposite the threaded end such that the ballengaged in the socket end. The drive shaft also includes an enlargedknobbed wheel disposed adjacent a proximal end opposite the distal end.This enlarge knobbed wheel is accessible through the sleeve.

The present invention is also directed to an intervertebral spacerinserter having a sleeve with a sleeve tip end and a connection tipextending out from the sleeve tip end. A sliding tip with an elongatedslot is included, and the connection tip extends through the elongatedslot. This sliding tip is in contact with the sleeve tip end and ismoveable with respect to the sleeve tip end between a first positionwith the connection tip disposed adjacent a first end of the elongatedslot and a second position with connection tip disposed adjacent asecond end of the elongated slot opposite the first end. In oneembodiment, the elongated slot has a midpoint between the first end andthe second end. The connection tip is disposed between the midpoint andthe first end when the sliding tip is in the first position, and theconnection tip is disposed between the midpoint and the second end whenthe sliding tip is in the second position.

In one embodiment, the sliding tip further has a first face in contactwith the sleeve tip end and a second face opposite the first face. Theelongated slot passes completely through the sliding tip from the firstface to the second face. When the sleeve tip end includes a flatsurface, the first face is in contact with the flat surface. Theintervertebral spacer inserter is provided with a first alignmentmechanism disposed between the flat surface and the first face to holdthe sliding tip in the first position; and a second alignment mechanismseparate from the first alignment mechanism and disposed between theflat surface and the first face to hold the sliding tip in the secondposition. In one embodiment, the first alignment mechanism includes afirst recess disposed in the first face, a first cavity disposed in theflat surface and a first spring loaded ball plunger disposed in thefirst cavity and biased outward from the first cavity toward the firstface. The first spring loaded ball plunger engages the first recess whenthe sliding tip is in the first position. Similarly, the secondalignment mechanism includes a second recess disposed in the first face,a second cavity disposed in the flat surface and a second spring loadedball plunger disposed in the second cavity and biased outward from thesecond cavity toward the first face. The second spring loaded ballplunger engages the second recess when the sliding tip is in the secondposition.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an embodiment of an intervertebralspacer inserter in accordance with the present invention;

FIG. 2 is a partial exploded view of the intervertebral spacer inserter;

FIG. 3 is a top view of one end of the intervertebral spacer inserterwith the sliding tip in the first position;

FIG. 4 is a top view of one end of the intervertebral spacer inserterwith the sliding tip in the second first position;

FIG. 5 is an end view of the sleeve tip end of the intervertebral spacerinserter with the sliding tip in the first position;

FIG. 6 is an end view of the sleeve tip end of the intervertebral spacerinserter with the sliding tip in the first position;

FIG. 7 is a view through line 7-7 of FIG. 3;

FIG. 8 is a view through line 8-8 of FIG. 5;

FIG. 9 is a view through line 9-9 of FIG. 6;

FIG. 10 is a perspective view of an end of the intervertebral spacerinserter with a spacer attached;

FIG. 11 is the view of FIG. 9 with the spacer attached;

FIG. 12 is the view of FIG. 8 with the spacer attached;

FIG. 13 is a front view of an embodiment of a bi-lateral reducer inaccordance with the present invention;

FIG. 14 is a side view of the bi-lateral reducer;

FIG. 15 is an exploded view of the bi-lateral reducer;

FIG. 16 is a partial perspective view of the bi-lateral reducer with thesagittal reducer and rotation arm attached to the screw stick;

FIG. 17 is a perspective view of an embodiment of hinged tab breaker inaccordance with the present invention;

FIG. 18 is a partial perspective view of an end of the hinged tabbreaker positioned over a reducing screw;

FIG. 19 is a partial perspective view of an end of the hinged tabbreaker positioned over a reducing screw with the screws tabs insertedinto the hinged tab breaker;

FIG. 20 is a partial cutaway view of an end of the hinged tab breakerpositioned over a reducing screw with the screws tabs inserted into thehinged tab breaker

FIG. 21 is a partial cutaway view of an end of the hinged tab breakerwith the screws tabs removed form the reducing screw;

FIG. 22 is a partial cutaway view of an end of the hinged tab breakerwith the screws tabs ejected from the hinged tab breaker

FIG. 23 is an exploded perspective view of an embodiment of aretractable rigid screwdriver in accordance with the present invention;

FIG. 24 is a perspective view of the retractable rigid screwdriver; and

FIG. 25 is a side view of the driver shaft and the retracting shaft ofthe retractable rigid screw driver.

DETAILED DESCRIPTION

Referring initially to FIGS. 1-9, an exemplary embodiment of the presentinvention is directed to an intervertebral spacer inserter 100. Theintervertebral spacer inserter facilitates minimally invasive techniquesfor spacer insertion in the thoracolumbar region of the spine using aside (lateral) surgical approach, such as lateral lumbar interbodyfusion (LLIF). The intervertebral spacer inserter can be used for eithera left or right side approach with a spacer having an off-center pointof connection. This is accomplished with an intervertebral spacerinserter having a curved tip end attached to a sliding tip. Asillustrated, the intervertebral spacer inserter 100 includes a sleeve102 running along a longitudinal axis 104 with a sleeve tip end 106 anda handle end 108 opposite the sleeve tip end 106. A handle, for example,a slap handle, is attached to the sleeve at the handle end. Suitablearrangements of slap handles are known and available in the art.

The sleeve includes a hollow sleeve bore 112 (FIGS. 2 and 7-9) extendingthrough the sleeve along the longitudinal axis from the sleeve tip endto the handle end. In one embodiment, the hollow sleeve bore has acircular cross-section. Disposed in the sleeve tip end 106 is an opening116 (FIG. 2), for example a circular opening, of a passage 118 (FIG. 7)that extends into the sleeve along a passage axis 120. The passage is incommunication with the sleeve shaft 112, and the passage axis 120intersects the longitudinal axis 104 at an angle 122 less than about90°. In one embodiment, the angle is about 15°. Alternatively, the angleis adjustable up to about 90°. This angle provides and defines thecurved tip end of the intervertebral spacer inserter. In one embodiment,the sleeve tip end has a flat surface 124 (FIG. 2), and the opening isdisposed on this flat surface. Preferably, the flat surface is disposedin a plane that extends perpendicular to the passage axis 120.

The intervertebral spacer inserter 100 also includes a sliding tip 126that is in contact with the sleeve tip end 106 of the sleeve.Preferably, the sliding tip end is a separate structure than the sleeve(FIG. 2) and can be completely separated and removed from the sleeve. Ingeneral, the sliding tip includes a first face 129 that faces or is incontact with the sleeve tip end. In one embodiment, the first face is incontact with the flat surface of the sleeve tip end. The sliding tipalso includes a second face 130 opposite the first face 129. The secondface 130 contacts or engages any spacer 131 (FIGS. 10-12) that isattached to the intervertebral spacer inserter. The sliding tip includesan elongated slot 128. The elongated slot 128 passes completely throughthe sliding tip from the first face to the second face. In order toprovide secure attachment of the sliding tip to the sleeve tip end, inone embodiment the first face is formed as a channel 132 (FIGS. 8 and 9)having a bottom surface 134. The sleeve tip end extends into thechannel, and the flat surface of the sleeve tip end contacts with thebottom surface of the channel. In order to constrain movement of thesliding tip relative to the sleeve tip end along a given line, thechannel has a dove tail shaped cross section (FIG. 7). The sleeve tipend is formed in a mating shape to the dove tail shaped channel.

The sliding tip can be any desired or suitable shape. In one embodiment,when viewed from the first or second faces, the sliding tip has agenerally rectangular shape. In this embodiment, the sliding tipincludes a first edge 138 and a second edge 139 disposed opposite thefirst edge. This defines a length 140 between the first and secondedges. In the rectangular arrangement, this length represents the longerlength of the rectangular shape of face of the sliding tip. The channelis aligned with this length, and the elongated slot is also alignedparallel to the length. Movement of the sliding tip relative to thesleeve tip end is also along the direction of this length. The elongatedslot includes a first end 142, a second end 144 and a midpoint 136between the first end and the second end. Preferably, the midpoint ofthe elongated slot is aligned with the midpoint of the length of thesliding tip. The sliding tip includes a pair of tangs 141 extending fromthe sliding tip away from the sleeve tip end. One tang is disposed ateach of the first edge and the second edge of the sliding tip.

The sliding tip moves with respect to the sleeve tip end between a firstposition (FIGS. 3, 5 and 8) with the opening accessible through theelongated slot and disposed adjacent a first end of the elongated slotand a second position (FIGS. 4, 6 and 9) with the opening accessiblethrough the elongated slot and disposed adjacent a second end of theelongated slot opposite the first end. Preferably, the opening isaccessible through the elongated slot and is between the midpoint andthe first end when the sliding tip is in the first position, and theopening is accessible through the elongated slot and is disposed betweenthe midpoint and the second end when the sliding tip is in the secondposition. Therefore, the sliding tip moves between two non-centered oroffset positions with respect to the its midpoint and the opening in thesleeve tip end, facilitating the use of the intervertebral spacerinserter in either a left or right side lateral approach.

In order to secure or hold the sliding tip in either the first or secondposition, alignment mechanisms are provided between the sleeve tip endand the sliding tip. Suitable alignment mechanisms can include, forsample, an indentation and a moveable member that is biased into theindentation when the sleeve tip end and the sliding tip are in thedesired arrangement. A single alignment mechanism can be provided forboth the first and second positions, or a separate alignment mechanismcan be provided for each one of the first position and the secondposition. In one embodiment, the alignment mechanism includes a firstalignment mechanism disposed between the flat surface and the first faceto hold the sliding tip in the first position and a second alignmentmechanism separate from the first alignment mechanism and disposedbetween the flat surface and the first face to hold the sliding tip inthe second position.

As illustrated in the drawings, the first alignment mechanism 150includes a first recess 152 disposed in the first face, a first cavity154 disposed in the flat surface and a first spring loaded ball plunger156 disposed in the first cavity and biased outward from the firstcavity toward the first face. The first spring loaded ball plungerengages the first recess when the sliding tip is in the first position(FIG. 8). The second alignment mechanism 160 includes a second recess162 disposed in the first face, a second cavity 164 disposed in the flatsurface and a second spring loaded ball plunger 166 disposed in thesecond cavity and biased outward from the second cavity toward the firstface. The second spring loaded ball plunger engages the second recesswhen the sliding tip is in the second position (FIG. 9).

The intervertebral spacer inserter includes a drive shaft 180 rotatablydisposed in the hollow sleeve bore. The drive shaft includes a distalend 182 disposed adjacent the sleeve tip end. In one embodiment, thedrive shaft includes an enlarged grooved or knobbed wheel 184 disposedadjacent a proximal end opposite the distal end and adjacent theattached handle. The enlarged knobbed wheel is accessible through thesleeve (FIG. 1). A connection tip 170 is provided that is rotatablydisposed in the passage and is in contact with the distal end of thedrive shaft. The connection tip includes a threaded end 172 that extendsout from the passage through the opening and the elongated slot.Therefore, the connection tip also prevents the sliding tip fromcompletely sliding off the sleeve tip end. The opposite end of theconnection tip is functionally engaged with the distal end of the driveshaft so that rotation of the drive shaft rotates the connection tip. Inone embodiment, the distal end of the drive shaft is shaped as a ball182, and the connection tip includes a socket end 174 opposite thethreaded end. The ball is engaged in the socket end to provide a workingconnection at the desired angle.

Rotation of the enlarged knobbed wheel rotates the drive shaft, whichrotates the connection tip. This provides for attaching or removing theintervertebral spacer inserter from a spacer 131 as illustrated in FIGS.10-12. Attachment and removal of the intervertebral spacer inserterinvolves threading the connection tip either into or out of acorresponding threaded shaft 190 or connection hole in the spacer. Thisthreaded shaft is offset from the center line 192 of the spacer.Therefore, the sliding tip 126 is placed in either the first position(FIG. 12) or the second position (FIG. 11) so that the connection tipaligns with the threaded shaft when the spacer is centered between thetabs 141 of the sliding tip. This provides for either a left or rightside lateral approach to the spine with the spacer extending the definedangle 194 from the longitudinal axis of the sleeve. This provides accessto L4-L5 disc level and the upper levels of the lumbar cord through LLIFusing spacers with an off-centered point of connection for both rightand left approaches.

Referring to FIGS. 13-16, the present invention is also directed to abi-lateral reducer 200 that is used to reduce a rod into an implant toachieve coronal plane reduction. In general, a side-loading pediclescrew system requires a tool to reduce the rod into the implant toachieve coronal plane reduction while still allowing sagittal planereduction to have the screw head meet the rod construction. Thebi-lateral reducer of the present invention combines coronal reductionwith implant rod holding sleeve insertion in the same tool. Sagittalreduction and implant rotation for alignment are achieved usingadditional instruments that are attached to the bi-lateral reducer.Therefore, the bi-lateral reducer provides for both coronal planereduction and sagittal plane reduction with a side-loading pedicle screwand rod implant.

In general, the bi-lateral reducer uses a plurality of structures orarmatures connected by a plurality of pins to provide coronal reduction.The bi-lateral reducer includes a pair of handles 202 pivotally attachedto each other. To one handle a rod slot arm 206 is pivotally attached.The rod slot arm 206 includes a rod slot 204 on an end opposite thepoint of attachment of the rod slot arm to the handle. The rod slot endincludes a curvature that is suitable for engaging and moving a rod.Pivotally attached to the other handle is a guide shaft attachment point224. A screw stick guide shaft 212 is inserted into the guide shaftattachment point and secured to the bi-lateral reducer. A tulip sleeveinserter 210 slides over the screw stick guide shaft. The tulip sleeveinserter includes a set screw 208. When the tulip sleeve inserter isplaced over the screw stick guide shaft, the set screw is turned toengage in a slot 214 in the screw stick guide shaft. This preventsremoval of the tulip sleeve inserter and defines a range of motion ofthe tulip sleeve inserter along the screw stick guide shaft. An end 224of the tulip sleeve inserter is configured to secure a rod holdingsleeve (not shown) for positioning over the rod following reduction. Theadditional tools for the bi-lateral reducer include a rotation arm 222and a sagittal reducer 218.

In order to use the bi-lateral reducer, a rod holding sleeve is attachedto the end of the tulip sleeve inserter. The tulip sleeve inserter andthe screw stick guide shaft are slid over a screw stick 220 that isattached to a patient implant. The bi-lateral reducer includes aprecision stick guide shaft to provide a close fit to the screw stick.The screw stick extends past the guide shaft attachment point, and therotation arm is attached to this exposed top portion of the screw stick.The sagittal reducer is also attached to the top portion of the screwstick between the rotation arm and the guide shaft attachment point.Moving the handles together in the direction of arrow A, moves the rodslot arm 206 in the direction of arrow B. This engages the rod slot ontothe rod, reducing the rod into the side loading pedicle screw implant.Preferably, the handles are ratcheted to assist in reduction and toprevent the rod from moving backwards once reduced, i.e., to hold thehandles in the closed position. Following reduction of the rod, thetulip sleeve inserter is moved in the direction of arrow C to insert therod holding sleeve onto the implant. With the rod reduced and held inplace with the sleeve, the bi-lateral reducer is removed, and a lockingnut is attached to more permanently secure the rod.

The bi-lateral reducer reduces through the coronal plane, and theadditional tools attached to the screw stick provide sagittal reductionand rotation of the implant. Rotation of the implant may be required toalign the rod with the rod slot for proper reduction. Sagittal reductionis achieved by applying distractive forces between the bi-lateralreducer and the implant through the screw stick. Therefore, completereduction of the rod is achieved without removing any of theinstruments. The bi-lateral reducer simplifies the surgical procedureand allows complete reduction and alignment of the rod to the implant aswell as locking the rod into the implant without removing any tools. Byusing the screw-stick on the implant, the bi-lateral reducer is easilyaligned and attached to the implant for rigid, assured reduction.

Referring to FIGS. 17-22, the present invention is also directed to ahinged tab breaker 300 for a reduction screw that can simultaneouslyremove both tabs from a single reduction screw. Typically, tabs areremoved from reduction screws using an instrument that grabs and breakseach individual tab one at a time. Since each reduction screw has twotabs and procedures may use a number of screws, the single tab breakingmethod is tedious and time consuming. The hinged tab breaker of thepresent invention breaks and removes both tabs from a single reductionscrew simultaneously, reliably and easily.

As illustrated, the hinged tab breaker 300 includes a pair of handlearms 302 attached at one end by a ratcheting arm 304. Therefore, whenthe arms are moved toward each other, they are held or locked in theposition by the ratcheting arm, which includes a releasing tab 305 torelease the arms for opening. A tip 306 is attached to the other end ofthe each arm. The tip is arranged as two identical tip portions set asmirror images of each other. Each tip portion of the tip includes apress tab 308 that can pivot with respect to the tip between a closedposition (FIGS. 20 and 21) and an open position (FIG. 22). This pivotalmovement exposes a retaining window inside each tip portion. Each presstab is biased in the closed position by a spring 316 or other suitablebiasing member. Pressing of the tabs in the direction of arrows F, movesthe tabs to the open position. A tulip collar 310 is attached to the endof the tip. The tulip collar is shaped to fit around the tulip head ofthe reduction screw and to cradle the rod 303 that is passing throughthe reduction screw.

The hinged tab breaker 300 is placed over the reduction screw 314 withthe tulip collar located over tulip head and the tabs 312 of thereduction screw (FIG. 18). The tulip collar is slid down over the tabs(FIG. 19), allowing the reduction screw tabs 312 to pass under thespring-loaded press tabs and into the retaining windows (FIG. 20). Theleading edge 319 of each press tab can be rounded, beveled, sloped orchamfered to facilitate passage of the screw tabs into the retainingwindows. The hinged tab breaker is lowered around the reduction screwuntil the screw tabs are seated against the back walls 317 of theretaining windows in the tip of the hinged tab breaker. The handles arethen squeezed together. The hinged handle arrangement bends the tabs ofthe reduction screw outward simultaneously, and pressure is applied onthe reduction screw tabs by rocking the hinged tab breaker back andforth in the direction of arrow D until the screw tabs break away fromthe tulip head of the reduction screw. At this point, the hinged tabbreaker is moved away from the reduction screw with the reduction screwtabs retained within the tip (FIG. 21). Therefore, the broken reductionscrew tabs 313 can be removed from the area of the reduction screws.Pressing the tabs 308 in the direction of arrows F releases the brokenreduction screw tabs 313 which pass out of the hinged tab breakerthrough the tulip collar in the direction of arrow G (FIG. 22).

By fitting around and stabilizing the lower part of the tulip head, thehinged tab breaker remains centered about the implant and equallydistributes the breaking force across both tabs. The tabs of thereduction screw fit into pockets or retaining windows in the tips of theinstrument, which are controlled to ensure that the instrument breaksthe tabs at the desired location along the length of each screw tab.Spring-loaded press tabs pinch against the tabs and retain them withinthe tips of the instrument. These components are rounded on the leadingedge to allow the tabs of the reduction screw to slide under them withlittle resistance upon insertion. The press tabs retain the tabs of thereduction screw after they are broken away from the implant tofacilitate easy removal. Compression of the spring under the press tabsallows easy release of the broken tabs for disposal.

Referring to FIGS. 23-25, the present invention is also directed to aretractable rigid screwdriver 400 for the insertion of pedicle screws orother bony anchors. The retractable rigid screw driver includes aretracting mechanism that prevents the screwdriver from becoming looseduring anchor insertion and allows for the retraction of the screwholding mechanism in-situ to provide visibility for driving the screw.The retractable rigid screwdriver 400 includes a handle 402 that isthreaded onto a tightening shaft 404. The handle can be removed, i.e.,unscrewed, from the tightening shaft, and the tightening shaft andhandle, when attached, can rotate independent of each other. Theretractable rigid screwdriver also includes a retracting shaft 418 thatcan fit inside the tightening shaft. The retracting shaft includes oneor more splayed tabs 422 that engage windows 406 running along the sideof the tightening shaft. Engagement of the splayed tabs in the windowsholds the tightening shaft 404 over the retracting shaft 416. This alsoprovides alignment between a gripping end 424 of the retracting shaftand a compression collar end 408 of the tightening shaft. Removing thehandle and depressing the splayed tabs permits complete removal oftightening shaft from the retractable rigid screwdriver for cleaning.The gripping end is split into a plurality of tabs or fingers, and whenthe compression collar end is over the gripping end, the fingers arecompressed and hold a screw for insertion and alignment. When thesplayed tabs are depressed, the tightening shaft is moved in thedirection of arrow H to uncover the gripping end.

A driver shaft 410 passes completely through the handle, tighteningshaft and retracting shaft. The driver shaft includes a proximal end 412extending past the handle and shaped to engage a driving device such asa wrench or other suitable driver. Suitable shapes for this proximal endinclude, but are not limited to square and hex heads. The distal end 414of the driver shaft opposite the proximal end is shaped to engage ascrew or bony anchor to rotate the anchor and drive the anchor into thedesired location in a bone. The distal end is generally disposedadjacent the gripping end 424 of the retracting shaft. A transverse pin416 is provided in the driver shaft. This pin engages an elongated slot420 on the retracting shaft to define the range of motion of theretracting shaft relative to the driver shaft. One end of this elongatedslot includes a spring lock 419 to hold the retracting shaft in aretractable position that exposes the distal end of the driver shaft.

A screw is placed in the gripping end of the retracting shaft. Thisscrew also engages the distal end of the driving shaft. The screw ismoved into alignment with the desired location for insertion. Theretracting shaft and tightening shaft are then moved in the direction ofarrow H to disengage the screw from the gripping end and to expose thescrew. The retracting shaft and tightening shaft are moved until thetransverse pin engages the spring lock in the elongated slot to hold theretractable rigid screwdriver in the retracted position. The screw isstill engaged with the distal end of the driving shaft. This providesincreased visibility of the screw during rotation and driving of thescrew by the driving shaft.

While it is apparent that the illustrative embodiments of the inventiondisclosed herein fulfill the objectives of the present invention, it isappreciated that numerous modifications and other embodiments may bedevised by those skilled in the art. Additionally, feature(s) and/orelement(s) from any embodiment may be used singly or in combination withother embodiment(s) and steps or elements from methods in accordancewith the present invention can be executed or performed in any suitableorder. Therefore, it will be understood that the appended claims areintended to cover all such modifications and embodiments, which wouldcome within the spirit and scope of the present invention.

What is claimed is:
 1. An intervertebral spacer inserter comprising: asleeve comprising: a longitudinal axis; a hollow sleeve bore extendingthrough the sleeve along the longitudinal axis; a sleeve tip end; and anopening of a passage disposed in the sleeve tip end, the passageextending into the sleeve to a sleeve shaft along a passage axis thatintersects the longitudinal axis at an angle less than about 90°; and asliding tip comprising an elongated slot, a first tang at a first end, asecond tang at a second end, and a length between the first and secondtangs, the sliding tip in contact with the sleeve tip end and moveablewith respect to the sleeve tip end between a first position with theopening accessible through the elongated slot and disposed adjacent thefirst end of the elongated slot and a second position with the openingaccessible through the elongated slot and disposed adjacent the secondend of the elongated slot opposite the first end, wherein the lengthbetween the first and second tangs is the same at the first position andat the second position.
 2. The intervertebral spacer inserter of claim1, wherein the sliding tip further comprises: a first face in contactwith the sleeve tip end; and a second face opposite the first face, theelongated slot passing completely through the sliding tip from the firstface to the second face.
 3. The intervertebral spacer inserter of claim2, wherein the sleeve tip end further comprises a flat surface disposedin a plane perpendicular to the passage axis, the opening disposed inthe flat surface and the first face in contact with the flat surface. 4.The intervertebral spacer inserter of claim 3, further comprising: afirst alignment mechanism disposed between the flat surface and thefirst face to hold the sliding tip in the first position; and a secondalignment mechanism separate from the first alignment mechanism anddisposed between the flat surface and the first face to hold the slidingtip in the second position.
 5. The intervertebral spacer inserter ofclaim 4, wherein: the first alignment mechanism comprises: a firstrecess disposed in the first face; a first cavity disposed in the flatsurface; and a first spring loaded ball plunger disposed in the firstcavity and biased outward from the first cavity toward the first face,the first spring loaded ball plunger engaging the first recess when thesliding tip is in the first position; and the second alignment mechanismcomprises: a second recess disposed in the first face; a second cavitydisposed in the flat surface; and a second spring loaded ball plungerdisposed in the second cavity and biased outward from the second cavitytoward the first face, the second spring loaded ball plunger engagingthe second recess when the sliding tip is in the second position.
 6. Theintervertebral spacer inserter of claim 3, wherein: the first facecomprises a channel having a bottom surface; the sleeve tip end extendsinto the channel; and the flat surface is in contact with the bottomsurface of the channel.
 7. The intervertebral spacer inserter of claim6, wherein the channel comprises a dove tail shaped cross section. 8.The intervertebral spacer inserter of claim 1, wherein: the elongatedslot comprises a midpoint between the first end and the second end; theopening is accessible through the elongated slot between the midpointand the first end when the sliding tip is in the first position; and theopening is accessible through the elongated slot between the midpointand the second end when the sliding tip is in the second position. 9.The intervertebral spacer inserter of claim 8, wherein the sliding tipfurther comprises: a first edge; and a second edge disposed opposite thefirst edge and defining a length between the first and second edges, theelongated slot aligned parallel to the length between the first andsecond edges.
 10. The intervertebral spacer inserter of claim 9, whereinthe first and second tangs extend from the sliding tip away from thesleeve tip end, the first and second tangs disposed at each of the firstedge and the second edge of the sliding tip, respectively.
 11. Theintervertebral spacer inserter of claim 1, further comprising: a driveshaft rotatably disposed in the hollow sleeve bore and comprising adistal end disposed adjacent the sleeve tip end; and a connection tiprotatably disposed in the passage and in contact with the distal end ofthe drive shaft, the connection tip comprising a threaded end extendingthrough the opening and the elongated slot.
 12. The intervertebralspacer inserter of claim 11, wherein: the distal end of the drive shaftcomprises a ball; and the connection tip further comprises a socket endopposite the threaded end, the ball engaged in the socket end.
 13. Theintervertebral spacer inserter of claim 11, wherein the drive shaftfurther comprises an enlarged knobbed wheel disposed adjacent a proximalend opposite the distal end, the enlarge knobbed wheel accessiblethrough the sleeve.
 14. The intervertebral spacer inserter of claim 1,wherein the angle comprises about 15°.
 15. The intervertebral spacerinserter of claim 1, wherein the angle is adjustable up to about 90°.16. The intervertebral spacer inserter of claim 1, further comprising aslap handle attached to the sleeve at a handle end opposite the sleevetip end.
 17. An intervertebral spacer inserter comprising: a sleevecomprising: a sleeve tip end; and a connection tip extending out fromthe sleeve tip end; and a sliding tip comprising an elongated slot, afirst tang at a first end, a second tang at a second end, and a lengthbetween the first and second tangs, the connection tip extending throughthe elongated slot, the sliding tip in contact with the sleeve tip endand moveable with respect to the sleeve tip end between a first positionwith the connection tip disposed adjacent the first end of the elongatedslot and a second position with connection tip disposed adjacent thesecond end of the elongated slot opposite the first end, wherein thelength between the first and second tangs is the same at the firstposition and at the second position.
 18. The intervertebral spacerinserter of claim 17, wherein: the elongated slot comprises a midpointbetween the first end and the second end; the connection tip is disposedbetween the midpoint and the first end when the sliding tip is in thefirst position; and the connection tip is disposed between the midpointand the second end when the sliding tip is in the second position. 19.The intervertebral spacer inserter of claim 17, wherein: the sliding tipfurther comprises: a first face in contact with the sleeve tip end; anda second face opposite the first face, the elongated slot passingcompletely through the sliding tip from the first face to the secondface; the sleeve tip end further comprises a flat surface, the firstface in contact with the flat surface; and the intervertebral spacerinserter further comprises: a first alignment mechanism disposed betweenthe flat surface and the first face to hold the sliding tip in the firstposition; and a second alignment mechanism separate from the firstalignment mechanism and disposed between the flat surface and the firstface to hold the sliding tip in the second position.
 20. Theintervertebral spacer inserter of claim 19, wherein: the first alignmentmechanism comprises: a first recess disposed in the first face; a firstcavity disposed in the flat surface; and a first spring loaded ballplunger disposed in the first cavity and biased outward from the firstcavity toward the first face, the first spring loaded ball plungerengaging the first recess when the sliding tip is in the first position;and the second alignment mechanism comprises: a second recess disposedin the first face; a second cavity disposed in the flat surface; and asecond spring loaded ball plunger disposed in the second cavity andbiased outward from the second cavity toward the first face, the secondspring loaded ball plunger engaging the second recess when the slidingtip is in the second position.